Color photography



'May 15, 1945. s w pg 2,376,217

COLOR PHOTOGRAPHY Filed April s,' 1943 FIG. 1

- BLUE SENSITIVE EMULSION YELLOW couPLER YELLOW E/LTER LA YER +MAGEN7A COUPLER RED :FENSITIVE EMULSION RED SENSITIVE EMULSION CYAN COUPLER SUPPORT LOT s. WILDER INVENTOR WEMM MAMS GREEN SENSITIVE EMULSION GREEN SENSITIVE EMULSION further object is to provide a method and means.

Patented May is, 1945 UNITED STATE ooLon rno'rocnArnY Lot S. Wilder, Rochester, N. Y.,'i assignor to Eastman Kodak Company, Rochester, N. Y., a corporation oi New Jersey Application April s, 1943,

Claims.

This invention relate to color photography and particularly to a multi-layer photographic Serial No. 481,988

material iorthe' preparation of colored pictures.

Theincorporation in photographic emulsions of compounds containing active methylene or phenolic hydroxyl groups which couple with the development product of primary aromatic amino photographic developers upon photographic development was described in Fischer U. S. Patent 1,102,028, June 30, 1914'. When such couplers are incorporated in multi-layer photographic mate- 'rial which contains emulsion layers sensitive to various regions of the spectrum, the couplers tend to reduce the sensitivity of the emulsion in which they are incorporated. One method which has been proposed for overcoming this objectionable action of the coupler compounds in.the emulsionsis, to incorporate the, couplers in a pure gelatin layer situation above or below the corre sponding sensitive silver halide, layer. This method is described in Schinzel U. S. Patent 2,306,410, December 29, 1942, on page 12. When thevcouplers are incorporated in a plain gelatin layer in this way, they do not reduce the sensitivity of the emulsion layer and a colored image can be produced. The development product of the developing agent diiiuses from the silver halide layer into the adjacent layer containing the coupler.. The image produced in this way, how grter, has poor definition and low maximum den It is, therefore, an object of the present invention to provide a multi-layerfilm containing couplers, which produces maximum dye densities. A

for diminishing the speed loss in photographic coatings containing couplers. A stilliurther object is to provide a method and means for imcoatings containing couplers. Other objects will appear from the iollowing' description of my invention.

These objects are accomplished by placing adsam'e In the accompanying-drawing, which forms a part of my invention, the Fig. 1 is a sectional view ot a fllm having sensitive layers not containing coupler coated layers'containing' con- -gi0ns, are coated in succession on a support. The

2,306,410, three silver halide emulsion layers, sensitive respectively to the red, green and blue rered-sensitive emulsion layer preferably contains a nonfdifiusing coupler capable .of producing a blue-green layers, the green-sensitive emulsion.

layer contains a non-diflusing coupler capable of producing aniagentadyeand the blue sensitive emulsion layercontains a non-dlfiusing coupler capable of producing a yellow dye. A yellow filter layer is ordinarily coated between the bluesensitive emulsion layer and the green-sensitive emulsion layer. The non-diffusing couplers incorporated in the sensitive emulsion layers in this way tend to decrease the sensitivity to light of suggested on page '12 of the emulsion layer, and, therefore; make it neces-.

sary to expose the materialto light of higher intensity or for a longer time in order to secure the. Schinzel necessary dye density, 'in the image.

his Patent 2,306,410 that the couplers might be incorporated in gelatin layers situated adjacent the corresponding silver halide layers. For example, the magenta coupler would be incorporated in a gelatin iayeradjacent the green-sensitive layer rather than incorporatedin the green-sensitive layer itself. This I expedient overcomes the objectionable desensitizing, of theeinulsion, layer but has the disadvantagethat the definition of the resulting images layer. of the same or is poorer and the maximum density lower than when the coupler is incorporated in the sensitive layer -itself. I

According to my. inventio I incorporate the layer itself in the cusprovide an extra sensitive faster silver halide without thevcoupler, adjacent the layer containing .the

tomarymanner but 1 coupler/ For example, adjacent the green-sensitive emulsion layer containing the coupler producing the magenta dye Iprovide a green-sensiv,tive silver-halide layer not containing coupler.

-. ver halide emulsion piers, and Fig. 2 is enlarged sectional view or a portion of 1.

In the known process oi producing col red pho tographlc imagesin a multi-layer material as described, for example. in Bchinsel U. 8. Pii'flit In ,the corresponding manner, a red-sensitive sillayer not containing coupler may be provided adjacent the red-sensitive emulsion layer containing the coupler producing the cyan dye. The presence of coupler in an unsansitized layer causes less speed loss thanin an op-- ticall sensitized layer,'hence the need for an extra emulsionlayer adjacent'the blue-sensitive layer containing the coupler producing the yellow but such layercan. be

dye is considerably less, emp d ..d i e Animor this typeis shown in the accompany- Ois abase or support of theticresimpaperor-celiuioseester.

onthismmportarecoatedsilverhalideemulsion.

.tocoatthelayerllnearestthesupportandto coat the layer II on the opposite side 0! the layer II. The iilm also has a yellow filter layer ll between layers It and ll. 0! any suitable lightabsorbing material such as colloidal silver.

Whenaiilmoithistypeisexposedtoacolored object or image containing the three primary colorsJatentimagesareproducedineaghoithe ilvesensitiveemulsionlayers. Itthefllmisto be developed to a color negative, it is developed:

immediately after exposure in a color-forming developer such as p-amine or diethyl-p-phenyl. This developnent step produces yellow, magenta and the respective emulsion layers containing these couplers. In the red-sensitive and green-sen.sitiveemulsionlayers and "not couplerasilverimagem-pmdueed with the color development; This developmen otsilverimageginlayers "and liresulmin the Iormationoi oxidation orpmd. uctsotthedevelopingagentandtheseoxidation or development products diiiuse somewhat into ofthetwolayersllandll oithefllmshowninl'ig. 1. areexposedbyredlightand devel color-forming developer, image I! willhe inlayer ll andimage ltwillbeformedinlayer ll. Theseimagesareindicatedinthedrawing as triangular figures, the left hand side indicating the portion of minimum density and the r t hand side the portion of maximum density.

lgage l'lwillconsistoimetalliesilverandcyan ll. Imageliwihconsistonlyoimetallicsilver becauselsyer ll containsnocoupler. Because otthereducedsensitlvity oi'layerll causedby theprmenceoithe coupler, theimage "has less drawing) thantheimagell.

toedensitythantheimage l8. Thisisindicated bytheiactthattheimage llextendsmrther totheleitmeyondtheverticaldottedlineinthe The developer oxidation product irom image ll difluses somewhat into layer II. when it enterslayer H itcomesincontactwithany coupler in that layer which has not already coupled. Cyan dye is thereby formed wherever the developer oxidation product from layer ll diiluses into layer-ll. Thisisindicated at it asathinportionoidyeneartheboimdaryoi' layers "and II. Since thedyeresultsiromsilwillserveto ver formation in layer II, it will extend further into the toe region than image ll andwhen the metallic silver is moved from layers II and M the toe density of image ll. 'flhis is equivalent to increasing thespeed oilayer In the production of a sensitive photographic film according to my invention, any known photographic silver halide emulsion oi' satisfactory speed and definition characteritlcs may be employed. The green-sensitive and red-sensitive emulsionhyers may contain any suitable optical semitisingdyesand theemulsioniaycrsmaycontain any or the non-dimming couplers described in 8611111881 11-8. Patent 2,308,410.

'l'hesensitiveemulsionlayerscontainingthe couplersmayalsobeofthewpeinwhichthe is incorporated in a water-insoluble,

water-permeable material as. described in thetheco llh 'ratloandthsthickawidevarletyoidesirablenegativeorreclnracteristicscanbeobtained. lnadditiontotge'meoihalide a silverhalide layer iree'otcmplerandhavingaspectralsensitivity same, and aspeedat leastas great, as that,of layer towhich itis contiguous,

7o pier being in contactwith no layerYo f diiTerent 2. A multi-layer photographic comprising a support having thereon-"fliree gelatinosilver halide emulsion layers sensitive -respecbecause 01' the coupler incorporatedin 75 tlvclmtothebluagreemandredspectralregions ing at least two silver halide'layers sensitive to different spectral regions, and containing cou-* and containing couplers, and contiguous to at least one of said emulsion layers sensitive to a wave-length longer than blue, a gelatino-silver halide emulsion layer free of coupler and having a spectral sensitivity substantially the same, 'and a speed at least as great, as that of the couplercontaining layer to which it is contiguous, said layer free of coupler being in contact with no layer of different spectral sensitivity containing coupler.

3. A multi-layer photographic material comprising a support having thereon three gelatinosilver halide emulsion layers sensitive, respectively, to the blue, green and red spectral regions and containing couplers contiguous to the greensensitive emulsion layer but not to the red-sensitive emulsion layer, a gelatino-silver' halide .emulsion layer sensitive to green light and free of coupler, and contiguous to the red-sensitive emulsion layer but not to the green-sensitive emulsion layer containing the coupler, a gelatino-silver halide emulsion layer sensitive to red light and tree of coupler, said layers tree of coupler having a speed as least as great as that o! the coupler-containing layer to which they are contiguous.

4. The method of increasing the dye densities in a multi-layer silver halide photographic material developed by color-forming development. which comprises in a, multi-lwer material havplers, incorporating contiguous to at least one of of said layers, a layer of silver halide free 7 of coupler and sensitive to the same spectral region and having a speed at-least as great as the coupler-containing layer to which it is contiguous, said layer free of coupler being in 'contact with no layer of different spectral sensitivity containing coupler, exposing and developing said material in-a color-forming developer whose development products difluse to some extent from the non-coupler-containing layer into the coupler-containing layer to strengthen the dye image in said last mentioned layer.

5. A multi-layer photographic material com-- prising a support having thereon three gelatinosilver halide emulsion layers sensitive, respectively, o the blue, green, and red spectral regions and co taining couplers, a yellow filter layer be;

tween the blue-sensitive and green-sensitive 

